TOOLKIT DOCUMENT
City/County of [NAME OF CITY]
Department of [NAME OF DEPARTMENT]
Code Requirement for Solar Photovoltaic (PV) Systems
Single Family Dwellings
Based on the 2010 California Building Code (CBC) and the 2010 California Residential
Code (CRC)
Purpose:
The purpose of this Information Bulletin is to clarify requirements of the State Building Standards Codes
(Title 24) that pertain to solar PV installations in Single Family Dwellings (SFD). This bulletin can serve
as a reference guide for permit applicants and enforcing agencies to clarify how state code requirements
are practically applied in the local jurisdiction. It is intended to minimize permitting uncertainty and
differing interpretation regarding specific code requirements for solar PV installations. This Information
Bulletin primarily clarifies requirements pertaining to the California Building Code and the California
Residential Code, since these codes in their current form require significant local interpretation. This
Information Bulletin does not address local regulations.
The implementation of uniform standards to achieve the timely and cost-effective installation is
consistent with the California Solar Rights Act that views solar installation as a matter of statewide
concern and prohibits local jurisdictions from adopting unreasonable barriers to the installation of solar
energy systems (CA Government Code Section 65850.5).
PART I: BUILDING AND RESIDENTIAL CODE REQUIREMENTS
1. Definitions:
1.1
Solar Photovoltaic (PV) System. The total components and subsystems that, in
combination, convert solar energy into electric energy suitable for connection to utilization
load (CEC Article 690.2)
1.2
Solar photovoltaic Module. A complete, environmentally protected unit consisting of solar
cells, optics, and other components, exclusive of tracker, designed to generate dc power
when exposed to sunlight (CEC Article 690.2)
1.3
Solar Photovoltaic (PV) Panel. A collection of modules mechanically fastened together,
wired, and designed to provide a field-installable unit (CEC Article 690.2)
1.4
Building Integrated Photovoltaics (BIPV). Photovoltaic cells, devices, modules, or modular
materials that are integrated into the outer surface or structure of a building and serve as
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the outer protective surface of the building (CEC Article 690.2)
2. Structural Requirements
2.1
PV Systems Positively Anchored to the Building:
2.1.1
Exemption from structural calculations: The Building Official may waive the
requirement for structural calculations for solar PV installations on top of existing
roofs if the official can readily determine that the additional weight of the new solar
PV system on the roof does not affect the structural integrity of the building. Some
jurisdictions may have a prescriptive approach for when structural calculations can
be waived, however, that varies by the enforcing agency.
To help streamline and simplify the permitting process for roof mounted solar PV
systems, it is highly recommended that local jurisdictions develop a prescriptive
approach to meeting the structural requirements so that structural calculations are
not always required. Here are some parameters to consider under such prescriptive
approach:
-
2.1.2
Maximum distributed weight of the solar PV system in psf
Maximum perpendicular distance between the solar PV system and the roof
below
Maximum concentrated load imposed by the PV panel support onto the
building’s roof
Minimum size and spacing of rafters or joists for portion of the roof that is
supporting the solar PV system
Maximum span of rafters or joists for portion of the roof that is supporting the
solar PV system
Anchoring requirements such as type of fasteners, minimum fastener size,
minimum embedment and minimum number of attachment points
Any limitation on the type of building construction
Structural calculations: When structural calculations are required, calculations shall
demonstrate that the primary structure will support the additional vertical and
lateral loads from the panels and related equipment.
2.1.2.1
Roof dead Load: The weight of solar PV systems shall be considered in
the design of the structure. (CRC Section R301.4)
For installation of conventional (not BIPV) solar PV panels on existing
roofs, the Building Official may allow a certain percent of the code
required live load to be reduced to accommodate the additional weight
of the solar PV panels provided the roof design is adequate for the
concentrated loads from the solar PV panel support frames. This
allowance may vary by jurisdiction and is generally based on the
assumption that solar PV panels will not be stepped on or used by
anyone to support any live load.
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When the roof live load is allowed to be reduced, consideration should
be given to the possibility that a roof may have more than one layer of
existing roofing and the possibility of having smaller size rafters in older
buildings.
2.1.2.2
Roof live load: The Building Official may allow the live load to be
reduced in the area covered by each solar PV panel when such area is
inaccessible as determined by the enforcing agency and as discussed in
Section 2.1.2.1 of this Information Bulletin. Roof surfaces not covered
by solar PV panels shall be designed for the roof live load. (CRC R301.6)
The Building Official may determine that Live load need not be
considered for solar PV panels and associated supporting members that
are built on grade. Such interpretation is generally based on the
assumption that the solar PV panels will not be stepped on or used by
anyone to support any live load
2.3
2.1.2.3
Wind design: Calculations shall demonstrate that the solar PV panels
and associated supporting members are designed to resist wind loads.
(CRC R301.2.1)
2.1.2.4
Seismic design: Calculations shall demonstrate that the solar PV panels
and associated supporting members are designed to resist earthquake
loads. (CRC 301.2.2)
2.1.2.5
For wood construction, supports shall be attached with fasteners of
sufficient length and size to achieve minimum required embedment into
solid wood taking into consideration the plywood and multiple layers of
roofing that may exist, unless otherwise approved by the enforcing
agency. (CRC Section R301.1.3)
2.1.2.6
Snow load: When applicable, include snow loads and loads from snow
drift. (CBC Section 1608, CRC R301.2.3)
2.1.2.7
Requirements for Load Combinations:
The applicable load
combinations in CBC 1605 may be applied to all loading conditions,
including evaluating the effects of dead load to counteract wind uplift.
(CRC Section R301.1.3)
Structural Strength of PV Panels: The structural strength of solar PV panels is not
addressed in the code.
UL 1703, Third Edition, published March 15, 2002, requires that solar PV panels are tested to
withstand a superimposed load of 30lb/ft2. Therefore, all solar PV panels that are listed per
UL 1703 are considered to meet this requirement.
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When used as a building component and depending on the load values that the solar PV
panels are subjected to, the enforcing agency may require a test report from an agency
recognized by the enforcing agency showing the strength of the solar PV panels.
2.4
Condition of existing roof: Solar PV systems shall not be installed on an existing roof that is
deteriorated to the point where it is not adequate as a base (this interpretation is based on
CRC R907)
2.5
Pre-manufactured support systems: Pre-manufactured support systems must support the
PV system and allow the system to stay attached to the structure when exposed to wind or
seismic activity. Compliance of the PV support system with appropriate building codes
is accomplished through a design specified by a licensed engineer or architect, or
through research reports from approved sources as defined in CBC Section 1703.4.2.
Additional requirements may be imposed by the enforcing agency. (CRC Section R301.1.3)
3. Fire Safety Provisions
3.1
Fire/roof classification of Photovoltaic (PV) Panels
3.1.1
Solar PV Panels Installed on Top of a Building’s Roof Structure:
3.1.1.1
Solar PV systems installed on top of a roof where the space between the
solar PV panels and the roof has no use and no potential use are
generally considered to be equipment. Currently, the State’s Building
Standards Code maintains fire/roof classification requirements for roof
structures, but does not maintain specific requirements regarding
fire/roof classification of solar PV panels.
Since no specific requirements or guidance are provided by the State
Building Standards Code, local enforcing agencies currently determine
whether any fire/roof classification of solar PV panels is required and if
so, what fire/roof classification is required. The State Fire Marshal is
leading an effort to consider specific state code requirements for
fire/roof classification of solar panels in the current code adoption
process. Until any requirements in this area are standardized on a state
basis, agencies generally consider the following when determining any
appropriate fire/roof classification to enforce:
•
UL 1703, Standard for Flat-Plate Photovoltaic Modules and Panels,
is often used for determining the fire/roof classification and
listing/certification of solar PV panels. This standard is not
currently listed in the CRC but is being considered for adoption in
the 2013 State Building Standards Code. UL 1703 is subject to
change until approved as part of state code. Enforcing agencies
may consider this standard as an alternate to UL 790, subject to
approval by the Building Official. (CRC Section R902)
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3.1.2
•
Local enforcing agencies have used different approaches to
determine any appropriate fire/roof classification for solar PV
panels. When PV systems cover a significant portion of the roof,
some enforcing agencies have determined that the solar PV panels
mounted above the roof should match the classification of the roof
while others have determined that the panel may be of a lesser
classification based on local conditions, panel installation
configuration
listing/certification
and/or
alternate testing
information.
•
For installations in State Responsibility Areas (SRA) or High Fire
Hazard Severity Zones, additional provisions adopted by the local
enforcing agency may be applicable. Check with the enforcing
agency for any additional requirements.
3.1.1.2
Solar PV Panels Used as Roofing on an independent (standalone)
structure: Solar PV panels/modules that are designed to be the roof, and
span to structural supports, and have a use or occupancy underneath,
shall comply with the minimum fire/roof classification requirements for
roof covering as required by CRC Section R902. An example of this type of
installation is a carport structure having solar PV panels as the roof.
3.1.1.3
Solar PV Panels Installed as a Part of a Building’s Roof Structure: Solar PV
panels installed as integrated roofing material shall comply with the
minimum fire/roof classification requirements for roof covering as
required by the current CRC Section R902. Example of this type of
installation is PV modules integrated into the roofing shingles (BIPV
systems).
Solar PV Systems installed on grade: Solar PV panels that are part of a stand alone,
ground mounted solar PV panel structures, with no use and no potential use
underneath are generally considered equipment and therefore the fire/roof
classification requirements would not apply. (Based on the definition of a roof
assembly in CRC Section R202)
3.2
Area, height, and story limitations: Where there is a use between the solar PV panels and
the roof/grade underneath, adding such solar PV structures may constitute additional floor
area, story and/or height. Solar PV panels supported by framing that has sufficient uniformly
distributed and unobstructed openings throughout the top of the array (horizontal plane) to
allow heat and gases to escape, as determined by the enforcing agency, are generally
considered equipment. (CRC Section 1.1.3, definition of a roof assembly in CRC Section R202)
3.3
Location from property line and adjacent buildings: Solar PV panels and associated framing,
with no use and no potential use between the panels and the grade underneath, are
generally treated as equipment; when not considered equipment, they may be considered a
structure and shall be located and protected based upon the code required fire separation
distance to property lines and adjacent buildings. (CRC Section R302.1)
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3.4
Other Fire Safety Requirements or Guidelines: The installation of solar PV systems may be
subject to additional provisions adopted by the local enforcing agency that may include the
State Fire Marshal Solar Photovoltaic Installation Guideline. Check with the enforcing
agency for
additional
requirements. The
guideline
can
be
obtained
at:
http://osfm.fire.ca.gov/pdf/reports/solarphotovoltaicguideline.pdf
4. Roof drainage: Roof mounted solar PV systems shall not cause excessive sagging of the roof that
results in water ponding. They shall also not block or impede drainage flows to roof drains and
scuppers. (CRC Section R903.4)
5. Roof penetrations: All roof penetrations shall be sealed using approved methods and products to
prevent water leakage. Such methods include but not limited to caulking, roof jacks and sheet metal
flashing. (CRC Section R903.2)
6. Skylights: Solar PV panels shall maintain a minimum clearance around the perimeter of skylights as
not to interfere with the function of the skylight, as determined by the enforcing agency (CRC
Section R303)
7. Plumbing vent, mechanical equipment and mechanical exhaust terminations: Solar PV panels shall
not obstruct or interfere with the function of plumbing vents or mechanical equipment. (CPC
Sections 901.1 & 906, CMC Section 304)
PART II. ELECTRICAL CODE REQUIREMENTS
1. Product Listing (Certification): The solar PV panel/module and other equipments used in the PV
system shall be listed/certified by a nationally recognized listing/certification agency in
accordance with the applicable standards.
2. Installation: The installation of the solar PV system must conform to the requirements of the
California Electrical Code (CEC).
3. Signage: Signage must conform to the requirements of the (CEC). Signage requirements and
location of certain equipment for solar PV systems may be subject to additional provisions
adopted by the enforcing agency that may include requirements from the State Fire Marshal
Solar Photovoltaic Installation Guideline.
PART III: LOCAL ELECTRIC UTILITY REQUIREMENTS
Check with the local utility for any incentives, interconnection, operating, and metering
requirements.
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